Aircraft position display

ABSTRACT

An onboard position display for aircraft, including a map located in the passenger compartment with lights on the map corresponding to Omni stations. A control unit operated by the pilot activates one of the lights, representing the Omni station used for navigation. The control unit includes a frequency select dial which is set on the same frequency used at the time for the Omni receiver. DME and To-From indications are also provided. A memory device permits a series of the lamps to be lighted representing the flight path, with the lamp for the closest station blinking.

United States Patent Danaher [451 May 2, 1972 [54] AIRCRAFT POSITIONDISPLAY [72] Inventor:

[73] Assignee: The Superior Oil Company, Houston, Tex.

[22] Filed: Aug. 30, 1968 [21] Appl. No.: 756,660

Harry C. Danaher, Houston, Tex.

[52] US. Cl. ..343/1l2 PT, 340/24, 340/27 NA, 343/106 R [51] Int. Cl..G0ls 5/02 [58] Field of Search ..343/1 12 PT, 106, 112 TC; 340/24, 27NAV [56] References Cited UNITED STATES PATENTS 3,009,147 11/1961Fernandez ..343/l12 PT UX 2,183,634 12/1939 Zworykin ....343/112 PT UXEbeling ....343/1 12 PT UX Cunningham ....343/112 PT UX Fernandez..343/1 12 PT UX 26 L VOMN/ #l 3,277,484 10/1966 Bostwick ..343/l073,505,640 4/1970 Cohen ..343/l06X Primary E.raminerBenjamin A. BorcheltAssistant E.\aminerRichard E. Berger Att0rney-Arnold, White & Durkee,Tom Arnold, Donald C. Roylance, Walter Kruger, Bill Durkee, Frank S.Vaden. ill and John G. Graham [57] ABSTRACT An onboard position displayfor aircraft, including a map located in the passenger compartment withlights on the map corresponding to Omni stations. A control unitoperated by the pilot activates one of the lights, representing the Omnistation used for navigation. The control unit includes a frequencyselect dial which is set on the same frequency used at the time for theOmni receiver. DME and To-From indications are also provided. A memorydevice permits a series of the lamps to be lighted representing theflight path, with the lamp for the closest station blinking.

20 Claims, 6 Drawing Figures PATENTEUMAY 21912 3. 660. 847

SHEETIBF 3 0: u E2 5% g N 4% 4t g) a gsg H. C. Danaher INVENTOR BYM,Qmf@1m2,

' ATTORNEYS PATENTEDMM 2 I972 SHEET 2 BF 3 HHIHIII IIIHIIIH lllllllllllllilllll lllllil I in m 4 H. C. Danaher IN VENTOR llama Qoylance, W l?Uunfiee A T TORNE YS P'A'TE'N'TEDMAY 21912 SHEET 3 OF 3 H. C. Danaher INVE N TOR A T TORNE Y5 When an aircraft is in flight, there is usually noway in which the passengers can determine the location of the plane.Landmarks are not visible from high altitude, particularly in badweather or at night, and even if visible are not familiar to laymen. Thepilot or navigator has precise information on the aircraft position atall times, but cannot interrupt his duties to convey this information tothe passengers, except quite infrequently, perhaps once during acommercial flight. Particularly for business travelers, concerned withappointments at their destination, the vacuum of information about theprogress of the aircraft during a several hour flight becomes quiteannoying. On small company-owned jets, the passengers are given torepeated inquiries to the pilot regarding location, expected time ofarrival, diversion of flight plan by weather, etc.. This distraction isnot conducive to safety, and further is not satisfactory to thepassenger who must leave his seat.

It is therefore a primary feature of this invention to provide positioninformation to passengers in aircraft in a continuous manner, withoutsignificant interruption of the cockpit crew. Another feature is theprovision of a visual display for the passenger compartment of anaircraft, which relates the position of the aircraft at the time to thegeographical area and/or to the flight plan, and particularly a displaywhich uses information already available in the cockpit withoutsubstantial additional duties for the crew in maintaining the displaycurrent.

In accordance with an exemplar embodiment of the invention, the positioninformation already existing onboard from Omni and DME equipment is usedfor a display in the passenger compartment. Omni transmitting stationsare spaced throughout the country in a fairly close pattern; a sequenceof quite a number of these stations is used in a transcontinentalflight. So, a rough approximation of the aircrafts location is providedby indicating which of the stations is being used by the pilot fornavigation. The exact position is pinpointed more precisely by alsodisplaying DME information and To-From information.

The display in the passenger compartment may well take the form of a maphaving lamps corresponding to each Omni station, with one of the lampsbeing lighted to indicate the station being used. A switch arrangementlocated in the cockpit is dialed to the same frequency numbers as theOmni receiver, either by separate knobs or by the same knobs as thereceiver itself, so the pilot need not do any calculation or exert anyother effort to select which light to turn on. A minimum of time on thepart of the crew, and no training at all, is needed to operate theposition display.

To account for the duplications in Omni frequencies used by stations inseparate parts of the country, the display board may be split up intogroups of lights which represent stations with no frequencies which arethe same. These groups conveniently represent geographical areascorresponding to the high altitude navigation charts published by thegovernment. Thus, the control unit includes an area select knob which ismerely set on the same number as the identifying number on the chartbeing used; in this manner the thought and distraction imposed upon thecrew is minimized.

By providing a memory unit for each lamp, a string of lamps may belighted to represent the flight path, and the lamps will remain onduring the entire flight. The closest station is indicated by blinkingthe corresponding light.

For commercial jets where the passenger compartment is quite large andthe passengers usually remain in their seats, it would be preferable tohave a display close enough to each passenger so that it may be readilyseen. Instead of having a large number of the display boards, the boardmay be shown on T. V. monitors of the type used for inflightentertainment. The position display may be run continuously on onechannel, while movies and T. V. programming are on the other channels.

Other information of interest may be made available at the positiondisplay board by merely repeating information available on indicators inthe cockpit. For example, airspeed, al-

titude, time, temperature, Mach number, etc., may be displayed.

THE DRAWINGS The novel features believed characteristic of the inventionare set forth in the appended claims. The invention itself, however, aswell as further features and advantages thereof, may best be understoodby reference to the following detailed description of particularembodiments, when read in conjunction with the accompanying drawings,wherein:

FIG. 1 is a pictorial view in schematic form of a position informationdisplay system for use in aircraft, according to the invention;

FIG. 2 is a schematic diagram of one embodiment of electrical circuitrywhich may be used in part of the system of FIG. 1;

FIG. 3 is a schematic diagram of another portion of the electriccircuitry used in one embodiment of the system of FIG. 1;

FIG. 4 is a detailed view in schematic form of a different arrangementfor mounting the frequency selector for the system of FIG. 1;

FIG. 5 is a schematic diagram of a memory circuit used in anotherembodiment of the system of FIG. 1;

FIG. 6 is a schematic pictorial view of a difierent embodiment of adisplay system according to the invention.

It is noted that like parts appearing in several views of the drawingsall bear like reference numerals. The drawings are considered a part ofthis specification and are incorporated herein.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS With reference now to FIG.1 of the drawings, one exemplar embodiment of an information displaysystem for aircraft, according to the invention, is illustrated inschematic form. This system includes principally a display board 10,which would be positioned in the passenger compartment of an aircraft,such as a business or commercial jet liner. The display board 10 shows amap of the United States, although it is understood that it mayillustrate only a localized area included in the flight plan, or anothergeographical region. In this regard, the front panel on the displayboard may be removable so that it may be replaced by a local map or amap of another country which the aircraft is to traverse. In any event,on the map 11 are superimposed a large number of small lights 12. Theselamps are positioned to coincide with the geographical locations of Omnitransmitters which contain DME signals incident thereto. There are manymore Omni stations for general aviation than would be convenientlyincluded on the map, so in the exemplar embodiment only the stationsused by high altitude jet aircraft are represented on the board 10 bylamps 12, since these are the only ones which would ever be used by thepilot of the aircraft of this type. Usually, these high altitudestations are also the only ones including DME signals. In particular,there are about of these stations used by high altitude aircraft in theUnited States.

It is noted that the map 1 l is divided into four quadrants 1 through 4this being necessary due to the fact that a given Omni frequency will berepeated several times throughout the continental United States. Forexample, Atlanta and Seattle stations might have the same frequency, sowhen this frequency is dialed only one lamp should light up. Thus, thequadrant of the flight path is selected by the pilot, and only thisquadrant will be operative at one time. Other areas outside thecontinental United States, such as Alaska and the Hawaiian Islands, maybe designated as further areas 5 and #6, as seen on the display board10.

Associated with the display board 10 is a further information display,including a distance indicator 14 which might contain informationderived from the DME (distance measuring equipment) associated with thehigh altitude Omni stations. A To-From indicator 15 is also provided,this information being derived from the same phase sensitive apparatuswhich provides the To-From indication for the Omni indicators in thecockpit. From these three indications, the particular lamp 12 which islit indicating which station is closest, the distance indicator l4 andthe To-From indicator 15, a passenger may readily determine the exactposition of the aircraft at any time, this information being producedwith a minimum of interruptions of extra duties for the pilot orco-pilot.

In addition, the display board includes an indicator 16 which readsground speed in miles per hour as derived from a Doppler radar typeground speed indicator of the kind usually included in aircraft of thistype. A mach indicator 17 is also provided to read the percentage ofspeed of sound, which of course may vary with altitude, humidity and thelike. A further indicator 18 reads the exterior temperature, which ofcourse would be of most significance or interest to the passengers whenthe aircraft has landed, rather than at high altitudes.

The display board 10 is controlled from the cockpit by a control panel20, which may be mounted on the overhead between the pilot and co-pilot.The control panel, explained here as being a separate unit, might becombined with the Omni and DME controls, as set forth below. A frequencyselect knob including a full megacycle control 21 and a tenths control22 is set by the pilot on the same Omni frequency to which the Omnireceiver is tuned for navigation purposes. Also, the pilot selects thequadrant or area, 1 through 6, by an area select knob 23 which functionsto enable any one of the lamps in one of the quadrants or areas to beenergized. The setting of the knobs 21 and 22 then energizes one, andonly one, of the lamps in this selected quadrant.

The quadrants or areas #1 through #4 coincide with the high altitude enroute charts published by the United States Coast and Geodetic Survey.So, the pilot or co-pilot merely sets the knob 23 on the same number asthe number of the high altitude chart he is using at the time.

The control panel 20 also includes an Omni select switch 24 and a DMEselect switch 25, these being for the purpose of determining the outputof which of the Omni units and which of the DEM units are displayed onthe To-From indicator l and the distance indicator 14 at the displayboard in the passenger compartment. The Omni and DME equipment 26ordinarily provided in an aircraft of this type includes two completesets of Omni and DME systems, with the To-From and range informationbeing applied to the control panel by a cable 27.

The Omni/DME equipment 26 would be operated in the usual manner.Ordinarily, the No. 1 set would be tuned to the Omni station ahead ofthe aircraft by the pilot, while the No. 2 set would be tuned to thestation behind the aircraft by the copilot. However, when making anapproach to land, the situation would be different since the outermarker and middle markers are referenced. In any event, the pilot wouldselect one or the other of the Omni units and the DME units to dis playthe most meaningful information to the passengers on the display board10.

A pulse control switch 28 on the control panel 20 actuates circuitrywhich provides an unusual visual efi'ect. By tuning the switch 28 onon," the lamps 12 on the display board are caused to flash on in aseemingly random fashion. This function would be used for decorativeeffect, rather than positional indication, when the aircraft is occupiedbut not in flight, as when waiting at the ramp or on the taxiway fortake-off. The circuitry for producing this pulse feature will bedescribed in detail below.

The control panel 20 is interconnected with the display board 10 by amulticonductor cable 29. In practice, the display board 10 would includeseveral distinct units, one of these being the map board itself withpermanently mounted lamps, wiring and certain relays. This portion wouldbe removable and replaceable so that various geographical areas would becovered. The display including the indicators 14 18 would be a unitapart from the map board. In addition, certain of the pulse and testcircuitry would be permanently associated with the display console,rather than being removable with the map.

Referring to FIG. 2, a simplified schematic diagram illustrates thecircuitry contained in the system of FIG. 1. The arrangement forselecting the particular one of the lamps 12 on the display board 10 tobe lighted will be first described.

The area select switch 23 is a seven-position rotary switch having amoveable contact 31 which is energized from a supply voltage source 32.Six of the stationary contacts are connected by six separate conductorsthrough a cable 33, which is part of the cable 29, to the coils of sixseparate area relays 34. Thus, when the moving contact 31 in the selectswitch 23 is on the first position, a positive voltage will be appliedto a terminal 35 of the coil 36 for area relay #1, the other terminal ofthe coil being grounded. This relay includes 10 separate parallel setsof contacts which are normally open but which all close simultaneouslywhen the coil is energized. All of the other area relays it 2 through 6are of exactly the same form as #1, but are illustrated in block formfor simplicity. As seen, when the area select switch 23 is set on aparticular area, this means that one and only one of the area relays lto 6 will be actuated. All of the others will have all of their contacts37 open.

The Omni frequency select switches, including the so-called megacycleswitch 21 and the tenths switch 22, are each separate l0-position rotaryswitches, although these are ordinarily physically mounted withconcentric shafts. The megacycle or megahertz select switch 21 includesa moving contact 41 which is connected to a positive voltage source 42.Since this will be the supply voltage for the lamps to be lighted, avariable resistor (not shown) may be in series with the supply 42 tocontrol the brightness of the lamps. The 10 stationary contacts for theswitch 21 correspond to the l0 full megacycle frequencies included inthe Omni range, i.e., 108 1 l7 megacycles. These 10 contacts areconnected separately through a cable 43, part of the major cable 29, toone side of each of the 10 contact pairs 37 for each of the area relaysNos. 1 6. Thus, depending upon the position of the moving contact 41,one of the lines in the cable 43 will have a positive voltage thereon,and this will be present on one side of this particular one of the tencontacts 37 in each of the area relays. Now, only one of the area relaysl to 6 is activated at one time, so only one of the output lines 44 willhave a positive voltage applied to it on the entire board. However,there may be several lamps in any quadrant or area which have a fullmegacycle frequency which is the same, such as 108.1 and 108.7, as seenin the diagram ofFlG. 2 as an example. Only one of these will belighted, however, due to the function of the tenths megacycle switch 22.

The tenths megacycle select switch 22 includes a moving contact 45 whichis connected to ground, while the 10 stationary contacts correspondingto .0 to .9 are separately connected by conductors in a cable 46, partof the cable 29, to 10 terminals at a terminal board 47. Thus, one ofthe 10 terminals of terminal board 47 will be grounded by the action ofthe switch 22, while the remainder will be open, If the moving contact45 is on the .1 contact, then only a lamp corresponding to a frequencyending in .1 can be lighted, such as 108.], 1 10.1, etc..

Considering now one of the lamps as an example to trace the circuit,there is seen that a lamp 12 corresponding to a 108.1 frequency has oneside connected by a conductor 48 to one of the output conductors 44 fromthe switches 37 in area relay 1, this output 44 corresponding to thefull megacycle frequency of 108 and thus being connected through thecable 43 to the first contact position of the rotary switch 21. If themoving contact 41 is on the first position, a positive voltage will thusbe applied to one side of this lamp at the conductor 48, in thisexample. The other terminal of this particular lamp is connected througha diode 49 to the .1 terminal at the terminal board 47, and thus by thecable 46 to the .1 position contact of the rotary switch 22. A circuitwill be completed to supply current through the 108.1 lamp in the area#1 relay quadrant, so if the area select switch 23 is also in the 1position, the contacts 37 will be closed and this lamp will light up.

The function of the diode 49 for this lamp, and similar diodes for allof the other lamps, is to prevent feedback from one lamp to others sinceone side of many of the lamps will be connected in common to the variousterminals 47.

Considering this same example of the 108.1 lamp in the first quadrant,it may be noted that a positive voltage will likewise be applied to oneside of a 108.7 lamp, or any other lamps corresponding to stations witha full megacycle frequency of 108. However, the 108.7 lamp will not belit, even though one side is energized, because the other terminal ofthis lamp will not be grounded. Instead, the .7 terminal in the terminalblock 47 will be open because, in this example, it is assumed that themoving contact 45 in the switch 22 is on .1, not .7. Further, otherlamps representing frequencies ending in .1, such as 110.1, will not belighted even though one side of such lamps is grounded through the .1terminal, because the 110 line in the output 44 from the area relay willnot have a positive voltage thereon. Moreover, a 108.1 lamp for thequadrant covered by the area relay 2 will not be lighted, even thoughone side is grounded at the .1 position of the terminal block 47,because the coil input 35 for this #2 relay will not be energized, themoving contact 31 in the area select switch 23 being on the 1 contact.Since its coil is not energized, all of the contacts 37 in the 2 relaywill be open, and so no positive voltage will be on any of the outputlines 44.

It may be noted that since there are output lines 44 for each area relayand ten terminals at the terminal block 47, there is provision for 100different frequencies in each area. However, each frequency will notoccur in each quadrant, so many possibilities will be unused.

There are, unfortunately, a few duplications of frequencies for highaltitude stations within a quadrant, so to avoid anomalies the leastused one of the duplicated frequencies may be merely omitted from themap; in the remote likelihood that the aircraft passes over thisstation, the map display would be briefly inoperative, or the frequencyfor the next following station could be set, in which case probably noDME information would be available.'lf stations with duplicatedfrequencies in a given quadrant are often used by a particular aircraft,one may be connected into the output of an adjacent area relay, and thisexception noted by the cockpit personnel in setting the control panel.

The circuitry for providing the pulse function will now be describedwith reference to FIG. 3. The test arrangement will also be describedsince it is interrelated with the pulse sequence. Generally, when thepulse switch 28 is closed at the control panel 20, a positive voltage isapplied through the cable 29 on a conductor 51 to energize a relay coil52. Also, this positive voltage is applied by a line 53 to all of theinputs 35 to the coils of the area relays so that all of the area relayswill be activated, closing their contacts 37, when the pulse switch 28is closed. The relay 52 includes three sets of normally open contacts.The first pair 54 functions to apply a positive voltage from a source 55to a line 56 which is connected through isolating diodes 57 to the tenconductors of the cable 43 or each of the cables 43, so that a positivevoltage is applied to one side of all of the lamps 12 on the entiredisplay board. Any of the lamps 12 may thus be turned on by groundingthe other side. To this end, all of the ground terminals 47 areconnected by the 10 conductors of the cable 46 to 10 contacts of arotary switch 58, through isolating diodes. A moving contact 59 for thisrotary switch is connected to ground through a pair of contacts 60operated by the relay coil 52. The moving contact 59 is operated by asmall D.C. motor 61 which is energized through a pair of contacts 62,also operated by the relay coil 52. Thus, when the relay coil 52 isenergized, the contacts 62 close and apply operating voltage to themotor 61 which then moves the contact 59in sequence through the 10contacts repeatedly. As the moving contact 59 engages each of the 10contacts, all of the lamps 12 on the board which represent frequenciesending in a given tenth megacycle will light up. At any instant,one-tenth of the lights on the board will be lit, but the visualimpression will be a random blinking of the lights. The rotary switch58-59 may be implemented by 10 microswitches and a cam arrangement forclosing the switches in an arbitrary sequence.

The test function is implemented by a press-to-test switch 64 seen inFIG. 3, along with an area select switch 65 seen in FIG. 2. Each area isseparately tested, so only one area lights up at one time. At thecontrol panel 20, the area select switch is moved to place the movingcontact 31 on the seventh position or T position so that no energizingvoltage is applied to any of the area relays from the switch 23. Theswitch 65 now controls, and is manually positioned in sequence toenergize each area relay as desired. With one area relay energized andthe others de-energized, the press-to-test switch 64 is depressedmanually, functioning to light all of the lamps 12 for this area. Whenthe switch 64 is depressed, a pair of contacts 66 are closed,functioning to ground all of the terminals 47 through the 10 lines ofthe cable 46 and isolating diodes 67, this path including a pair ofcontacts 68 operated by a relay coil 69. The function of the relay 69and its normally closed contacts 68 is to prevent the test circuitryfrom being operated while the pulse sequence is energized. Thus, thecoil 69 is connected to the line 51, so whenever the switch 28 is closedthe coil 69 is energized and the contacts 68 will be open, preventingany effect of closing the contacts 66 by the press-to-test switch.

Depressing the switch 64 will also operate contact 70 to apply positivevoltage directly from the source 55 to the line 56, bypassing thecontacts 54, so that a positive voltage will be applied to the 10conductors of the cable 43 to all of the contacts 37 in all of the arearelays. For the particular area relay which is activated, a positivevoltage will be applied to all of its lamps 12. Since the other side ofthese lamps will be grounded through the contacts 66, 68, all of thelamps for this area should be lighted. If any are not, they may bereplaced or the malfunction determined.

It is noted that resistors are shown in series with the power supply atone point or another in each of the different circuit functions. Forexample, a resistor 71 in series with the ground side of the pulsecircuitry is needed because not as many of the lamps will be lit duringpulse as during the test function. No limiting resistor is shown inseries with the ground side of the test circuitry, i.e., the circuitincluding the switches 66 and contact 68. A resistor 72 in series withthe positive side for both the pulse and test functions, i.e., in serieswith the source 55, is illustrated. This may be a variable resistor. Notshown are variable resistors in series with the power supplies, eitherin the positive or negative side, for the routine display function whereonly one lamp would be on. This may be considered brilliance orluminescence control and would be located at the display board tocontrol the brightness of the lamp, as for day or night operation.

As explained above, the frequency selector switches 21 and 22 may bemounted on the same shaft as the frequency select knobs for the Omniequipment itself, rather than at a separate control console 20. Such anarrangement is illustrated in FIG. 4, where it will be understood thatthe two concentric shafts would control the variable reactances for theOmni receiver, and would also mechanically rotate the moving contacts 41and 45 for the frequency select switches. Thus, when an Omni station isdialed for navigation, the display board 10 indicates the same stationwithout further action by the pilot or co-pilot. Of course, area selectand Omni l and 2 and DME 1 and 2 selections would still have to beprovided on the control panel 20, but the actions by the cockpitpersonnel would be greatly reduced.

Another embodiment of the invention is illustrated with reference toFIG. 5. A memory unit is provided for each of the lamps 12 so that astring of lamps may be lighted to indicate the flight path from take-offto landing, while only one of the lamps indicating the closest stationwould be blinking on and off. In FIG. 5, only one of the lamps 12 withits associated isolating diode 49 is illustrated, although all otherlamps would have the same memory arrangement. The lamp 12 of FIG. 5 isconnected on one side through one of the area relay output lines 44 andby one of the conductors of the cable 43 through the switch 21 to apositive supply 42', as in FIG. 2. But here, the positive supply is apulse source, as will be explained. The negative side of the lamp 12 isselectively grounded through a diode 49 and one of the terminals 47, asbefore. To provide the memory function, there is connected in serieswith each of the lamps 12 a controlled rectifier 75 or similar switchingdevice. The anode of the controlled rectifier is connected to a positivesupply through a Reset switch 76, this being a normally closedpush-button switch. So long as the switch 76 is closed, the positivevoltage will be available at the anode of all of the controlledrectifiers 75, there being one of these devices 75 for every one of thelamps 12. The cathode of each controlled rectifier is coupled to adifferent one of the lamps 12, so it is seen that there are twodifferent paths for lighting each lamp, one through the circuitry justas in FIG. 2, i.e., the output lines 44, etc., and the other through theassociated controlled rectifier 75 for this lamp. The characteristic ofa controlled rectifier of this type is that once the device is turnedon, it will continue to conduct until its anode voltage is reduced tozero or below a threshold. The device is turned on by a positive currentpulse applied to its gate electrode 77. Such a current pulse is providedthrough the collector-emitter path of an NPN transistor 78 if thistransistor is turned on by a voltage appearing on the base of thistransistor, this base being connected across the lamp by a line 79. Thecollector voltage for the transistor 78 is provided through a Set switch80. The Set and Reset switches 80 and 76 would be located on the controlpanel 20.

The arrangement thus far described functions to maintain a positivevoltage on the plus side of any lamp 12 which is ad dressed," even afterthe frequency select knobs 21 and 22 are turned to another frequency,and regardless of which area the area select may be turned to. However,since the ground or negative is removed when another lamp is addressed,another memory function is provided for each lamp on the ground side.This second memory function includes another controlled rectifier 81having its anode connected directly to the ground side of the lamp,while the cathode is connected to ground (or a voltage supply ofanegative magnitude sufficient to cause the device to conduct when itsanode is almost at ground). The gate of the SCR 81 is connected to thecollector of a PNP transistor 82, and the emitter of this transistor isconnected to the positive supply through the Set switch 80. The base ofthe transistor 82 is connected to the ground side of the lamp 12, sothis transistor can be turned on only if this particular lamp isgrounded through the tenths switch 22.

In operation of the embodiment of FIG. 5, a string of lamps 12 would belighted to indicate the flight path by the following procedure. The Omnistations over which the flight plan will carry the aircraft are firstselected by the pilot, co-pilot or navigator. Then, before take-off,each of these frequencies in the quadrants to be traversed is dialed onthe frequency select knobs 21 and 22. After each specific frequency isdialed, the Set button 80 is pressed. This applies a positive voltage tothe collector of all of the transistors 78, and the emitter of all ofthe transistors 82, there being one of each of these transistors forevery one of the lamps 12. Only one of the transistors 78 will turn onand conduct current to the gate 77 of its associated controlledrectifier, however, because only one of these transistors will have apositive voltage applied to its base via the line 79. This is becausethe supply voltage from the source 42 will be applied only to theparticular one of the lamps 12 associated with this particular selectedfrequency and quadrant. So, pressing the Set switch 80 will gate on thecontrolled rectifier 75 for the selected lamp, but none of the others.At the same time, the controlled rectifier 81 for this lamp will begated on, so ground will be maintained for this lamp regardless of whatis subsequently done with the selector switches 21 and 22. Then, whenthe next frequency is dialed, the positive voltage from the source 42will be removed from the line 44 for this previously selected lamp andwill be applied to another lamp. Nevertheless, the prior lamp willcontinue to be lighted because its controlled rectifiers 75 and 81continue to conduct. Accordingly, every lamp which is dialed or"addressed" will remain lighted. In this manner, every lamp for everystation along the flight plan to be used for navigation may be turned onbefore take-ofi. Then, during the flight, when each station is againdialed, as these stations are used for navigation, each of these lampsin sequence will again be "addressed. Now, the function of the pulsatingsource 42 will be apparent. The voltage supplied by the source 42switches between a positive voltage sufiicient to light the lamps and alower voltage sufficient to cause some current from the rectifi er 75 topass through the source 42' on the negative half cycle rather thanthrough the corresponding lamp 12, but not low enough to eliminate anycurrent flow through the lamp and through the SCR 81, so the ground paththrough the SCR 81 will not be extinguished. Thus, the lamp for the Omnistation being used will, when addressed, blink at the rate determined bythe squarewave source 42', while the others will remain energizedsteady. The rectifier 75 for the addressed lamp will not be extinguishedbecause it will continue to conduct on the lamp-off cycles through thesource 42, as well as slightly through the lamp.

Accordingly, using the memory arrangement of FIG. 5, a string of lampswill be lighted, but one will be blinking during flight in accordancewith the nearest Omni station or the one being used for navigation. Theboard is reset by pressing the reset button 76 which breaks the circuitto all of the controlled rectifiers, turning them off.

With reference to FIG. 6, an embodiment of the invention is illustratedwhich is particularly adapted for use in commercial aircraft having aclosed circuit T. V. system with individual T. V. monitors and channelselectors for each passenger or for each small group of passengers. Inthis embodiment, a display board 10 of the same type described above,would be positioned in a remote location in the aircraft and would havea closed circuit T. V. camera 84 trained thereon. The video output wouldbe transmitted by the usual cables to all of the T. V. monitors 85. Achannel selector 86 would be provided each seat or group of seats sothat a passenger could select live T. V. programming, movie, exteriorsight-seeing, or the positional information from the display board 10,as desired. Of course, air speed, DME, To-From, outside temperature,time and other information could be simultaneously displayed as before.Instead of showing the entire map, the camera 84 may be focused orzoomed in upon a localized area to improve resolution of the exactposition.

While the invention has been described with reference to particularillustrative embodiments, this description is not to be construed in alimiting sense. Various modifications of the disclosed embodiments, aswell as other embodiments of the invention, may be apparent to personsskilled in the art upon reference to this description. It is thereforecontemplated that the appended claims will cover an such modificationsor cmbodiments as fall with the true scope of the invention.

What is claimed is:

1. Position display apparatus for use on an aircraft or the likecomprising:

a display board positioned in the passenger compartment of the aircraftand exhibiting a map-like indicia,

a large number of lamps arranged on the display board to correspond togeographical positions of selected transmitting stations, with one lampfor each station, certain ones of the lamps being connected together ingroups corresponding to geographical regions which generally contain notwo of such stations transmitting at the same frequency,

a distance indicator associated with said display board and operative todisplay a number corresponding to the distance between the aircraft andthe station for a particular lamp,

an orientation indicator associated with said display board andoperative to indicate relative positional information.

2. Apparatus according to claim 1 wherein the transmitting stations areOmni stations, the distance indicator displays D- ME information, andthe orientation indicator displays To- From" information.

3. Apparatus according to claim 1 wherein only one lamp is lit at onetime, corresponding to one of the closest transmitting stations, andwherein the distance indicator corresponds to the energized lamp.

4. Apparatus according to claim 1 wherein a control device is providedin the cockpit of the aircraft whereby the pilot may selectivelyenergize particular lamps corresponding to the transmitting station usedfor navigational purposes.

5. Apparatus according to claim 1 wherein means are provided forselecting a particular one of said groups corresponding to the regiontraversed by the aircraft.

6. A position indicator system for the passenger compartment of anaircraft or the like comprising:

a display panel exhibiting a map-like indicia,

a plurality of lamps fixed on the display panel, each corresponding tothe geographical position of a different navigational signal transmitterin the geographical area traversed by the aircraft, I

control means located in the vicinity of the pilot compartment andeffective to actuate automatically selected lamps indicating the flightpath of the aircraft, one lamp being actuated in a different characterto indicate the approximate position of the aircraft.

7. A position indicator system for the passenger compartment of anaircraft or the like comprising:

a display panel exhibiting a map-like indicia,

a plurality of indicator means fixed on the display panel, eachcorresponding to the geographical position of a different navigationalsignal transmitter in the geographical area traversed by the aircraft,said indicator means being arranged in groups on the display panel tocorrespond to geographical regions which contain virtually notransmitters operating at the same frequency,

control means located in the vicinity of the pilot compartment andeffective to actuate automatically selected indicator means, theindicator means being selected corresponding to a transmitter used fornavigation of the aircraft.

8. A system according to claim 7 wherein the control means includesswitching means set by frequency, and area select means to enable onlyone of such groups to be energized.

9. A system according to claim 8 wherein the geographical regions aredefined according to navigational charts, whereby the area select meansmay be controlled according to the chart used for navigation of thecraft.

10. A system according to claim 9 wherein the area select means includesa multiple contact remotely actuatable switching device for each suchgroup.

11. A system according to claim 10 wherein the switching means includestwo separate multiple contact switches, one corresponding to the fullinteger megacycle Omni frequency select and the other corresponding totenth megacycle select.

12. A system according to claim 11 wherein the switching means isoperated by mechanical means coupled to the switches used for selectingthe Omni station used for navigation.

13. A system according to claim 11 wherein each lamp includes a memorydevice to maintain the lamp in an energized state after the lamp hasbeen actuated from the switches until the lamps are reset.

14. A system according to claim 13 wherein a pulsating electrical sourceis applied to one of such lamps to indicate the closest one of a numberof transmitting stations along a previously indicated flight path.

15. A position indicator system for the passenger compartment of anaircraft or the like comprising:

a display panel exhibiting a map-like indicia, said display panel beingpositioned remotely from the passenger compartment, means forreproducing the display panel in the passenger compartment by a closedcircuit type television arrangement,

a plurality of indicator means fixed on the display panel, eachcorresponding to the geographical position of a different navigationalsignal transmitter in the geographical area traversed by the aircraft,

control means located in the vicinity of the pilot compartment andeffective to actuate automatically selected indicator means, theindicator means being selected corresponding to a transmitter used fornavigation of the aircraft.

16. A system according to claim 15 wherein a plurality of channels oftelevision programming are provided for the passengers, and selectionmeans are provided therefor.

17. A system according to claim 16 wherein the camera for the televisionarrangement may be trained upon only a part of the map.

18. Positional display apparatus for use in a moving vehicle comprising:

a visual display panel exhibiting geographical information,

a plurality of lamps associated with the display panel and correspondingin relative position to navigational radio transmitters, said lampsdirectly indicating the location of the vehicle with respect to thegeographical information exhibited on said visual display panel,

means for automatically actuating said lamps in accordance with saidnavigational radio transmitters, said means for automatically actuatingincluding switch means corresponding to frequency select means used fortuning receiver means to the radio transmitters.

19. Apparatus according to claim 18 wherein said lamps are groupedaccording to geographical regions which generally contain no suchtransmitters operating on the same frequency, and the means forselectively actuating includes means for selecting one of said groups.

20. Apparatus according to claim 19 wherein means for indicatingdistance between the vehicle and the reference, are associated with thedisplay panel.

1. Position display apparatus for use on an aircraft or the likecomprising: a display board positioned in the passenger compartment ofthe aircraft and exhibiting a map-like indicia, a large number of lampsarranged on the display board to correspond to geographical positions ofselected transmitting stations, with one lamp for each station, certainones of the lamps being connected together in groups corresponding togeographical regions which generally contain no two of such stationstransmitting at the same frequency, a distance indicator associated withsaid display board and operative to display a number correspondiNg tothe distance between the aircraft and the station for a particular lamp,an orientation indicator associated with said display board andoperative to indicate relative positional information.
 2. Apparatusaccording to claim 1 wherein the transmitting stations are Omnistations, the distance indicator displays ''''DME'''' information, andthe orientation indicator displays ''''To-From'''' information. 3.Apparatus according to claim 1 wherein only one lamp is lit at one time,corresponding to one of the closest transmitting stations, and whereinthe distance indicator corresponds to the energized lamp.
 4. Apparatusaccording to claim 1 wherein a control device is provided in the cockpitof the aircraft whereby the pilot may selectively energize particularlamps corresponding to the transmitting station used for navigationalpurposes.
 5. Apparatus according to claim 1 wherein means are providedfor selecting a particular one of said groups corresponding to theregion traversed by the aircraft.
 6. A position indicator system for thepassenger compartment of an aircraft or the like comprising: a displaypanel exhibiting a map-like indicia, a plurality of lamps fixed on thedisplay panel, each corresponding to the geographical position of adifferent navigational signal transmitter in the geographical areatraversed by the aircraft, control means located in the vicinity of thepilot compartment and effective to actuate automatically selected lampsindicating the flight path of the aircraft, one lamp being actuated in adifferent character to indicate the approximate position of theaircraft.
 7. A position indicator system for the passenger compartmentof an aircraft or the like comprising: a display panel exhibiting amap-like indicia, a plurality of indicator means fixed on the displaypanel, each corresponding to the geographical position of a differentnavigational signal transmitter in the geographical area traversed bythe aircraft, said indicator means being arranged in groups on thedisplay panel to correspond to geographical regions which containvirtually no transmitters operating at the same frequency, control meanslocated in the vicinity of the pilot compartment and effective toactuate automatically selected indicator means, the indicator meansbeing selected corresponding to a transmitter used for navigation of theaircraft.
 8. A system according to claim 7 wherein the control meansincludes switching means set by frequency, and area select means toenable only one of such groups to be energized.
 9. A system according toclaim 8 wherein the geographical regions are defined according tonavigational charts, whereby the area select means may be controlledaccording to the chart used for navigation of the craft.
 10. A systemaccording to claim 9 wherein the area select means includes a multiplecontact remotely actuatable switching device for each such group.
 11. Asystem according to claim 10 wherein the switching means includes twoseparate multiple contact switches, one corresponding to the fullinteger megacycle Omni frequency select and the other corresponding totenth megacycle select.
 12. A system according to claim 11 wherein theswitching means is operated by mechanical means coupled to the switchesused for selecting the Omni station used for navigation.
 13. A systemaccording to claim 11 wherein each lamp includes a memory device tomaintain the lamp in an energized state after the lamp has been actuatedfrom the switches until the lamps are reset.
 14. A system according toclaim 13 wherein a pulsating electrical source is applied to one of suchlamps to indicate the closest one of a number of transmitting stationsalong a previously indicated flight path.
 15. A position indicatorsystem for the passenger compartment of an aircraft or the likecomprising: a display panel exhibiting a map-like indicia, said displaypanel being positioned remotEly from the passenger compartment, meansfor reproducing the display panel in the passenger compartment by aclosed circuit type television arrangement, a plurality of indicatormeans fixed on the display panel, each corresponding to the geographicalposition of a different navigational signal transmitter in thegeographical area traversed by the aircraft, control means located inthe vicinity of the pilot compartment and effective to actuateautomatically selected indicator means, the indicator means beingselected corresponding to a transmitter used for navigation of theaircraft.
 16. A system according to claim 15 wherein a plurality ofchannels of television programming are provided for the passengers, andselection means are provided therefor.
 17. A system according to claim16 wherein the camera for the television arrangement may be trained upononly a part of the map.
 18. Positional display apparatus for use in amoving vehicle comprising: a visual display panel exhibitinggeographical information, a plurality of lamps associated with thedisplay panel and corresponding in relative position to navigationalradio transmitters, said lamps directly indicating the location of thevehicle with respect to the geographical information exhibited on saidvisual display panel, means for automatically actuating said lamps inaccordance with said navigational radio transmitters, said means forautomatically actuating including switch means corresponding tofrequency select means used for tuning receiver means to the radiotransmitters.
 19. Apparatus according to claim 18 wherein said lamps aregrouped according to geographical regions which generally contain nosuch transmitters operating on the same frequency, and the means forselectively actuating includes means for selecting one of said groups.20. Apparatus according to claim 19 wherein means for indicatingdistance between the vehicle and the reference, are associated with thedisplay panel.